I'd like to choose random samples from multispectral image according to each Land Cover image. The multiband image has 70 bands representing land surface temperature data from MODIS. Land cover image has 9 classes. I need 50 sample (pixel) values of each land cover type which extracted from each band of multispectral image. How can I choose these random samples in ARCGIS, ERDAS and EVI? ENVI can be used to choose random samples on multiband image as ROI. But statistic output of ROI gave me the descriptive statistics of mean of all sample. What I want is the mean value of each separate samples of each land cover types in each bands.

Thanks in advance

  • Why do you want to sample the image when you can--with even less work--obtain statistics for the image itself?
    – whuber
    Feb 15, 2015 at 21:52

1 Answer 1


With ArcGIS, you can

1) convert your land cover image to polygons

2) dissolve all polygons based on the land cover field

3) generate 50 random point for each land cover polygon (select your land cover feature class as "constraining feature class")

4) Extract multiple values to points (this will give you the 70 band values as fields in the point feature class)

  • Thank you Radouxi, Can you tell me ,what kind of tool can be used to generate random point in ARCGIS? Can you give me step by step instruction, I'm new in this field. Feb 26, 2014 at 2:28
  • if you click on the link in my answer, you will have the help for the build in tool that is available if you have a spatial analyst licence.
    – radouxju
    Feb 26, 2014 at 7:08
  • I tried to use "Extract Values to Points" tool in spatial analyst tool. But it doesn't work on multiband image. Feb 28, 2014 at 4:23
  • It does work if you select the bands (in "input raster", double click on your raster to see the list of bands, select all bands)
    – radouxju
    Feb 28, 2014 at 6:42
  • 1
    Maybe you could post what you did in ENVI as a question that you answer yourself. By the way, I see that you mentioned "extract value to points", but I was talking about "extract MULTI values to point"
    – radouxju
    Feb 28, 2014 at 9:53

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